LA500 opto comp leveling amp BUILD THREAD 500/51X

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Re: LA500 opto comp leveling amp BUILD THREAD 500/51X

Post by Joe Malone »

kante1603 wrote:
G-Sun wrote:Hi!

My meter-light died.
How may I replace it?
Hello G-sun,

the squared and the round part can be detached.Take care when doing that,gently tear them apart.No brutal force please,or you might damage the meter or bend the needle.
Then gently tear apart the white inlay.
After that you can reach the led.Take care while unsoldering and soldering a new one in,also watch polarity.

Have attached a pic,hope that helps.

Meter opened.JPG

Best regards,

Udo.
Thanks Udo

Do just as Udo said :-)
Joe :-)
JLM Audio
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G-Sun
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Re: LA500 opto comp leveling amp BUILD THREAD 500/51X

Post by G-Sun »

kante1603 wrote:
G-Sun wrote:Hi!

My meter-light died.
How may I replace it?
Hello G-sun,

the squared and the round part can be detached.Take care when doing that,gently tear them apart.No brutal force please,or you might damage the meter or bend the needle.
Then gently tear apart the white inlay.
After that you can reach the led.Take care while unsoldering and soldering a new one in,also watch polarity.
Thanks a lot Udo!
Tried to use my LA500 today, but turns out it's more than the light.
Seems like meter is moving correct GR/Level, but it's not compressing and the Gain-pot is not doing anything.
Any pointers to the cause of the problem?
www.g-sun.no/en/

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Re: LA500 opto comp leveling amp BUILD THREAD 500/51X

Post by Joe Malone »

G-Sun wrote:
kante1603 wrote:
G-Sun wrote:Hi!

My meter-light died.
How may I replace it?
Hello G-sun,

the squared and the round part can be detached.Take care when doing that,gently tear them apart.No brutal force please,or you might damage the meter or bend the needle.
Then gently tear apart the white inlay.
After that you can reach the led.Take care while unsoldering and soldering a new one in,also watch polarity.
Thanks a lot Udo!
Tried to use my LA500 today, but turns out it's more than the light.
Seems like meter is moving correct GR/Level, but it's not compressing and the Gain-pot is not doing anything.
Any pointers to the cause of the problem?
Email me some clear in focus photos of your build so I can check it over. And answer all of the below questions.

Does the meter light? If NO link over the outside 2 terminals on the meter with a piece of wire to bypass the led and check if the comp is now working except for light not going. (If the led is blown the comp will never come out of bypass mode otherwise.)

Does threshold turn the level down ? Does GR meter show reduction?

Does makeup turn the level up?
Joe :-)
JLM Audio
Capturing Audio without Injury

G-Sun
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Re: LA500 opto comp leveling amp BUILD THREAD 500/51X

Post by G-Sun »

Joe Malone wrote: Email me some clear in focus photos of your build so I can check it over. And answer all of the below questions.
The unit has worked perfect for some 3 years.
Please tell me if you need the pictures after reading this post.
Does the meter light? If NO link over the outside 2 terminals on the meter with a piece of wire to bypass the led and check if the comp is now working except for light not going. (If the led is blown the comp will never come out of bypass mode otherwise.)
There is no light.
Does threshold turn the level down ? Does GR meter show reduction?
No, there is no audio GR, but the meters show GR.
Does makeup turn the level up?
No

Your explanation that the unit does not come out of bypass-state, caused by the VU-led, makes very much sense.
Meters is showing GR, and VU-out is reacting to GR and MakupGain.

If you don't tell me other-wise, I'll just test with bypassing led, and then change led.
What's the specs for a replacement led?

Very helpful answer :)
www.g-sun.no/en/

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Re: LA500 opto comp leveling amp BUILD THREAD 500/51X

Post by Joe Malone »

G-Sun wrote:
If you don't tell me other-wise, I'll just test with bypassing led, and then change led.
What's the specs for a replacement led?

Very helpful answer :)
Yes first try a wire across the outside terminals of the meter to bypass the led and see if the comp works without led just to check all the wiring is ok.

Led is white clear 5mm about 800 to 1000mcd. We have the LED as spare part on our website if you are trying to match other LA500 meter lights exactly. Open the meter as Udo showed to check led hasn't broken off one of the mounting posts if comp has been working so long. If still soldered in place replace led. New led must go in same way around Anode & Cathode and face the top of the meter. In LA500 you can unclip back of meter without removing wires or meter from the metal frame.
Joe :-)
JLM Audio
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Re: LA500 opto comp leveling amp BUILD THREAD 500/51X

Post by G-Sun »

Joe Malone wrote: Yes first try a wire across the outside terminals of the meter to bypass the led and see if the comp works without led just to check all the wiring is ok.

Led is white clear 5mm about 800 to 1000mcd. We have the LED as spare part on our website if you are trying to match other LA500 meter lights exactly. Open the meter as Udo showed to check led hasn't broken off one of the mounting posts if comp has been working so long. If still soldered in place replace led. New led must go in same way around Anode & Cathode and face the top of the meter. In LA500 you can unclip back of meter without removing wires or meter from the metal frame.
Thanks a will!
Was hitting the replacement led in your shop until 20aud for shipping :)
I'll have a look another place
www.g-sun.no/en/

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Re: LA500 opto comp leveling amp BUILD THREAD 500/51X

Post by G-Sun »

Now, look here:
IMG_20171031_101626965.jpg
Seems like we've found the course.
Remember when soldering that this spot seemed a little weak :)

Fixed. Working perfect again. Thank you!
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www.g-sun.no/en/

kante1603
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Re: LA500 opto comp leveling amp BUILD THREAD 500/51X

Post by kante1603 »

G-Sun wrote:Now, look here
Seems like we've found the course.
Remember when soldering that this spot seemed a little weak :)

Fixed. Working perfect again. Thank you!
Looks like an LA500A to me,not LA500.
Wrong thread......?

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Re: LA500 opto comp leveling amp BUILD THREAD 500/51X

Post by Joe Malone »

Cool great to hear it was a simple solder joint to fix :-)

This is a LA500A not LA500 so I will move it over to the LA500A build thread
Joe :-)
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studiomollan
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Re: LA500 opto comp leveling amp BUILD THREAD 500/51X

Post by studiomollan »

Hi,
If you were to try and fit an original T4B module in here, where would it go? I just replaced a drip t4b for a kenetek in a diy LA2a and it made such a huge difference. Im not saying the la500 sounds bat the way it is, i love mine, but would be fun to hear the difference.
/
Emil

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Re: LA500 opto comp leveling amp BUILD THREAD 500/51X

Post by Joe Malone »

studiomollan wrote:Hi,
If you were to try and fit an original T4B module in here, where would it go? I just replaced a drip t4b for a kenetek in a diy LA2a and it made such a huge difference. Im not saying the la500 sounds bat the way it is, i love mine, but would be fun to hear the difference.
/
Emil
The LA500 cannot run a luminescent cell as they need 40vac to 200vac to light. So T4B will never work in LA500.
Joe :-)
JLM Audio
Capturing Audio without Injury

studiomollan
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Re: LA500 opto comp leveling amp BUILD THREAD 500/51X

Post by studiomollan »

Ok. then i know. Thanks joe!

Alexcook
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Joined: Tue Oct 24, 2023 11:22 pm

Broken LA500

Post by Alexcook »

Hi, this is my first post so excuse my incompetence.

I’ve inherited a dropped LA500, the original one without the push pots. Its working as far as it switches on and lights up.

When i engage the compression the signal drops to almost inaudible, and a load of low end hum comes in. The signal as far as i can here is compressing however and the meter is just about moving

I have a video but it wont let me attach it

What could this be? Any help greatly appreciated as i’d love to get into using this thing on my projects

Thanks
Alex

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Re: Broken LA500

Post by Joe Malone »

Alexcook wrote:
Wed Oct 25, 2023 7:49 pm
Hi, this is my first post so excuse my incompetence.

I’ve inherited a dropped LA500, the original one without the push pots. Its working as far as it switches on and lights up.

When i engage the compression the signal drops to almost inaudible, and a load of low end hum comes in. The signal as far as i can here is compressing however and the meter is just about moving

I have a video but it wont let me attach it

What could this be? Any help greatly appreciated as i’d love to get into using this thing on my projects

Thanks
Alex
I have moved this post to the LA500 build thread.

Do the LA500/BIO500 test below. And let me know if the BIO500/LA500 pcb is working correctly or not. Attached well lit in focus photos of the assembled LA500 and tops of the pcb with JLM99v removed

Test BIO500/LA500 main pcb by itself by unplugging BIO500/LA500 main pcb ribbon cable from LA500SC pcb and fitting two cut-off component leg loops as shown below.
You should have a unity gain audio loop if BIO500/LA500 main pcb is working. This test proves BIO500/LA500 main PCB and output transformer are both working.
You can plug the relay green wire loop in and out to switch between bypass and BIO500 audio path to check the audio level is correct.
Image
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Joe :-)
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